Circuit breaker control system



July 5,1938. A. E. ANDERSON 2,123,034

CIRCUIT BREAKER CONTROL SYSTEM v Filed Sept. 4, 1956 Fig.1.

JOE;

S Attorrweg.

Patented July 5, 1938 UNITED STATES PATENT OFFICE Arvid E. Anderson,Drexel Hill, Pa., assignor to General Electric Company, a corporation ofNew York Application September 8 Claims.

My invention relates to circuit breaker control systems and particularlyto systems for controlling the closing of a circuit breaker, and oneobject of my invention is to provide an arrangement for limiting thetime that the closing circuit of a circuit breaker remains energized incase the circuit breaker fails to close in response to the energizationof the circuit.

In certain types of automatic circuit breaker reclosing systems, it isthe practice to effect the initial reclosure as quickly as possibleafter the circuit breaker opens. When such a system is used with acircuit breaker that is not provided with a latch checking switch, thereis the possibility that the closing circuit may be completed before thelatching means of. the circuit breaker has reset. When this occurs, theclosing circuit remains energized for a relatively long time withouteffecting the closing of the circuit breaker. If the circuit breakerclosing means is of the intermittently rated type, this relatively longenergization of the closing circuit may result in the burning out of theoperating coil of the closing means, which is connected in the closingcircuit. In accordance with my invention, I provide an arrangement forlimiting the time that the circuit breaker closing circuit remainsenergized in case the circuit breaker fails to close in response to theenergization of the circuit.

My invention will be better understood from the following descriptionwhen taken in connection with the accompanying drawing, Fig. 1 of whichdiagrammatically illustrates an automatic reclosing circuit breakersystem embodying my invention, and Figs. 2 and 3 illustratemodifications of the timing means which may be employed to effect theopening of the circuit breaker closing circuit, and its scope will bepointed out in the appended claims.

Referring to Fig. 1 of the drawing, I represents a circuit breaker whichconnects a suitable source of current such as a polyphase alternatingcurrent supply circuit 2 to a polyphase load circuit 3. The circuitbreaker I is shown as a latched-in circuit breaker having a closing coil4 which, when energized, closes the circuit breaker I, and over-currenttrip coils 5 which are arranged to be energized respectively inaccordance with the current flowing in different phases of the loadcircuit 3 and which, when sufiiciently energized, releases a latch 6that holds the circuit breaker in its closed position.

For effecting the automatic reclosing of the circuit breaker I, Iprovide a motor-driven timer I3 which is arranged to be set intooperation 4, 1936, Serial No. 99,441

when the circuit breaker I opens. In the particular arrangementdiagrammatically shown, the timer I3 comprises a motor I4 driving threecams I5, I6, and II, which respectively operate movable contacts I8, I9,and 20. The movable contacts I8, I 9, and 20 are shown in the positionsthey occupy when the circuit breaker I is closed under normal loadconditions. It will be noted that under these conditions the movablecontact 23 is held in engagement with the stationary contact 23 by alatch 2I which is arranged to be released by a magnet 22, the circuit ofwhich is completed through auxiliary contacts 30 on the circuit breakerI as soon as it opens. The magnet 22 also controls contacts in theclosing circuit of the control relay 25 so that this relay is energizedimmediately after the circuit breaker I opens, to effect an immediatereclosure of the circuit breaker, since the relay 25 when energizedcompletes an energizing circuit for the closing coil 4 of the circuitbreaker I.

In accordance with my invention, I provide in the closing circuit of thecontrol relay 25 the normally closed contacts 26 and provide suitabletiming means for effecting the opening of these contacts 26 after theclosing circuit has been completed, for a sufiicient length of time toeffect under normal conditions the closing of the circuit breaker I. Asshown in Fig. 1, the movement of the movable contact 20, when releasedby the magnet 22, allows the spring-actuated rod 21 to move downwardlyagainst the force exerted by a suitable retarding means, such as adashpot 28, to open the contacts 26 a predetermined time after themagnet 22 is energized.

The operation of the arrangement shown in Fig. 1 is as follows: When thecircuit breaker I is closed and the current supplied to the load circuit3 through the circuit breaker I is below a predetermined value thevarious devices are in the positions shown in the drawing. When anoverload occurs on the load circuit 3, one or both of the over-currenttrip coils 5 become sufficiently energized to release the latch 6 andthereby effect the opening of the circuit breaker I so that itsauxiliary contacts 30 and 3I are closed and its auxiliary contacts 32are open. The closing of the contacts 30 completes an energizing circuitfor the magnet 22 through the movable contact 20 and the stationarycontact 23 of the timer I3 and the contacts 26. By closing its contacts33, the magnet 22 completes a locking circuit for itself which isindependent .of the movable contact 20 and the stationary contact 23 sothat when these contacts are subsequently separated,

the energizing circuit of the magnet 22 is not interrupted. By actuatingthe latch 2 I, the magnet 22 releases the movable contact 20 so that itimmediately moves out of engagement with stationary contact 23 and intoengagement with stationary contact 35. A circuit is then completed forthe control relay 25 through the auxiliary contacts 3i of the circuitbreaker I, the contacts 34 of. the magnet 22, contacts 35 and 20 of thetimer I3, contacts 33 of the magnet 22, and the contacts 26. By closingits contacts 31, the relay 25 completes an energizing circuit for theclosing coil 4 to efiect a substantially instantaneous reclosure of thecircuit breaker I.

The closing of the contacts 30 when the circuit breaker I opens alsocompletes a starting circuit for the driving motor I4 of the timer I3through the stationary contact 39 and the movable contact I8 of thetimer I3, the driving motor I4, and the movable contact I9 and thestationary contact 40 of the timer I3. Immediately after the motor I4starts, the cam I5, which is rotated in a counter-clockwise direction,causes the movable contact I8 to move out of engagement with contact 39and into engagement with contact 4| so as to maintain an energizingcircuit for the motor I4 completed after the circuit breaker l closes.

If the circuit breaker I remains closed after the initial reclosure, theoperation of the timer l3 effects no change in the energization of thecircuits until the timer r aches its lockout position, in which positionthe cam I6 moves the movable contact I9 out of engagement with thecontact 40 so that the circuit of the motor I4 is interrupted and movesthe contact l9 into engagement with the contact 42. Since the circuitbreaker I is closed, the circuit of the motor I-i is then closed throughthe auxiliary contacts 32 on the circuit breaker I to complete anenergizing circuit for the motor 14 so that the timer is moved to itsnormal position, in which position the Cir-- cuit of the motor I4 isopen at the auxiliary contacts 30 of the circuit breaker I.

If the abnormal condition still exists on the load circuit 3 when thecircuit breaker I recloses, the trip coil 5 is again energizedsufficiently to effect the immediate opening of the circuit breaker I.The circuit breaker I is not immediately reclosed after this openingbecause the movable contact 20 is now in engagement with contact 35instead of being held in engagement with contact 23 by the latch 2!. Thecircuit breaker l remains open until the timer has been. in operationfor a sufficient length of time for the cam I! to effect first themovement of the movable contact 20 into engagement with contact 23 so asto complete the above-described energizing circuit for the magnet 22 andthen has effected the movement of the movable contact 20 into engagementwith contact 35 to complete the above-described energizing circuit ofthe control relay 25 to effect the reclosing of the circuit breaker I.

If the circuit breaker fails to remain closed after its secondreclosure, the motor-operated timer I3, in the particular arrangementshown in the drawing is arranged to effect another re closure of thecircuit breaker in the manner above-described. When the timer reachesits lockout position, contacts I9 and 4% are opened and I9 and 42closed. If the circuit breaker I is open, the energizing circuit of themotor I t is open at the auxiliary contacts 32 of the open circuitbreaker I so that the timer remains in this lockout position.

If for any reason the latch 5 fails to reset before the closing coil 4is energized after the circuit breaker I opens, the energization of theclosing coil 4 does not efiect the closing of the circuit breaker I andconsequently the magnet 22 and the control relay 25 and the closing coil4 remain energized. A predetermined time after the movable contact 2!!moves out of engagement with the contact 23, the spring-actuated rod 21effects the opening of the contacts 26 in the circuits of the magnet 22and the control relay 25 so as to effect the deenergization of theseelectromagnetic responsive devices as Well as the closing coil 4 inorder to prevent any of them from being damaged due to overheating. Thedashpot 28 is adjusted so that the contacts 2'6 open substantiallyimmediately after the closing circuit has remained energized long enoughto effect normally the closing of said circuit breaker. When the cam I!again moves the movable contact 20 into engagement with the contact 23,it also restores the spring actuated rod 21 to its normal position sothat the contacts 26 are closed to permit the timer l3 to attemptanother reclosure of the circuit breaker.

In the modification shown in Fig. 2, the contacts 26 are shown ascontacts of a time delay mercury switch, examples of which are Wellknown in the art, which is arranged to be tilted by the actuation of thespring-actuated rod 21 so that when the contact 20 is moved out ofengagement with contact 23, the switch is tilted in such a manner thatthe mercury moves away from the contacts 26 through a small orifice andafter a predetermined time opens the circuit through these contacts.

In the modification shown in Fig. 3, the contacts 26 are shown ascontacts of a time delay relay 50 which may be of any suitable type, examples of which are well known in the art. The circuit of this relay 50is completed when the contacts 34 of the magnet 22 are closed and themovable contact 2a of the timer I3 is in engagement with the contact 35.

While I have, in accordance with the patent statutes, shown anddescribed my invention as applied to a particular system and asembodying various devices diagrammatically indicated, changes andmodifications will be obvious to those skilled in the art, and Itherefore aim in the appended claims to cover all such changes andmodifications as fall Within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is:

1. In combination, a circuit breaker, a closing circuit, meansresponsive to the energization of said circuit for effecting the closingof said circuit breaker, means responsive to the closing of said circuitbreaker for opening said circuit, means for opening said circuitbreaker, and means responsive to the opening of said circuit breaker foreffecting the energization of said closing circuit and the opening ofsaid circuit substantially immediately after said circuit has remainedenergized long enough to effect normally the closing of said circuitbreaker.

2. In combination, a circuit breaker, a closing circuit, meansresponsive to the energization of said circuit for efiecting the closingof said circuit breaker, means responsive to the closing of said circuitbreaker for opening said circuit, means for opening said circuitbreaker, normally closed contacts in said circuit, means responsive tothe opening of said circuit breaker for energizing said circuit, andtiming means for opening said contacts a predetermined time after saidcircuit is energized.

3. In combination, a circuit breaker, a closing circuit, meansresponsive to the energization of said circuit for effecting the closingof said circuit breaker, means responsive to the closing of said circuitbreaker for opening said circuit, means for opening said circuitbreaker, normally closed contacts in said circuit, reclosing meansresponsive to the opening of said circuit breaker for effecting animmediate energization of said circuit, and timing means responsive tothe operation of said reclosing means for opening said normally closedcontacts a predetermined time after said circuit is energized.

4. In combination, a circuit breaker, a closing circuit, meansresponsive to the energization of said circuit for effecting the closingof said circuit breaker, means responsive to the closing of said circuitbreaker for opening said circuit, means for opening said circuitbreaker, normally closed contacts in said circuit, reclosing meansresponsive to the opening of said circuit breaker for effecting aplurality of energizations of said circuit with predetermined timeintervals between successive energizations, and timing means operativeafter each energization of said circuit to effect the opening of saidnormally closed contacts.

5. In combination, a circuit breaker, a closing circuit, meansresponsive to the energization of said circuit for effecting the closingof said circuit breaker, means responsive to the closing of said circuitbreaker for opening said circuit, means for opening said circuitbreaker, normally closed contacts in said circuit, means for biasingsaid contacts to their open position, a latch for holding said contactsin their closed position, means for delaying the opening of saidcontacts when said latch is released, and means responsive to theopening of said circuit breaker for efiecting the reclosure of saidcircuit breaker and the release of said latch.

6. In combination, a circuit breaker, a closing circuit, meansresponsive to the energization of said circuit for effecting the closingof said circuit breaker, means responsive to the closing of said circuitbreaker for opening said circuit, means for opening said circuitbreaker, normally closed contacts in said circuit, means for biasingsaid contacts to their open position, a latch for holding said contactsin their closed position, means for delaying the opening of saidcontacts when said latch is released, means responsive to the opening ofsaid circuit breaker for effecting a plurality of energizations of saidcircuit with predetermined time intervals between successiveenergizations, and means responsive to each energization of said circuitfor effecting the release of said latch.

7. In combination, a circuit breaker, a closing circuit, meansresponsive to the energization of said circuit for effecting the closingof said circuit breaker, means responsive to the closing of said circuitbreaker for opening said circuit, means for opening said circuitbreaker, normally closed contacts in said circuit, means responsive tothe opening of said circuit breaker for effecting a plurality ofenergizations of said circuit with predetermined time intervals betweensuccessive energizations, and means responsive to each energization ofsaid circuit for effecting the opening of said normally closed. contactsafter a predetermined time.

8. In combination, a circuit breaker having intermittently rated closingmeans, means responsive to the closing of said circuit breaker forrendering said closing means inoperative, means for opening said circuitbreaker, and means responsive to the opening of said circuit breaker foreffecting the operation of said closing means and for rendering saidclosing means inoperative substantially immediately after said closingmeans has been in operation long enough to efiect normally the closingof said circuit breaker.

ARVID E. ANDERSON.

